Field of the Invention
The present disclosure relates to an image formation apparatus capable of switching and thus running a plurality of OSs and a non-transitory computer-readable storage medium having stored thereon a program executable on such an image formation apparatus.
Description of the Related Art
Computer virtualization technology is being applied to various fields as information communication technology progresses in recent years. In such virtualization technology, for example a hypervisor can be utilized so that in addition to a main OS (Operating System) (hereafter also referred to as a “host OS”), one or more different OSs (hereafter also referred to as a “guest OS”) can be running on common hardware simultaneously.
For example Japanese Laid-Open Patent Publication No. 2001-256066 discloses an environment in which a plurality of operating systems allowed to co-exist in a single system can be rapidly switched and thus used.
Furthermore, “IBM PowerVM Virtualization Active Memory Sharing”, Second Edition (June 2011), IBM International Technical Support Organization, June 2011 discloses a system in which a plurality of logic memory partitions (LPAR: Logical PARtitions) are collected as a single common physical memory space and shared and thus used between multi-OSs as what is assigned logic memory partition.
Generally, when in addition to a host OS one or more guest OSs are running simultaneously, then, in proportion to the number of OSs (guest OSs in particular) running, a larger memory space is required. Accordingly, many virtualization technologies are equipped with a scheme which permits overcommitment when an upper limit of a system memory prepared in hardware is exceeded as a guest OS is running. For example Japanese Laid-Open Patent Publication No. 2014-157476 disclose a configuration which senses that a physical resource shared between virtual machines runs out.
A specific example of the scheme which permits overcommitment includes a processing in which a memory area utilized as a memory space is ensured in a secondary storage device such as a hard disk and a content stored in a system memory is temporarily restored to the ensured memory area.
However, a secondary storage device such as a hard disk is inferior in responsiveness to a system memory such as dynamic random access memory (DRAM), and accordingly, requires a long period of time to switch to a guest OS from a host OS for example. Such an issue is difficult to resolve when a limited resource is used. If a sufficiently large resource is prepared, a possibility that such an issue will arise can be reduced.
An image formation apparatus is also unable to allow available resource to be so large due to a constraint on cost. In particular, it is general to adopt hardware having a merit in terms of cost, rather than hardware having a high processing performance such as state-of-the-art computing environments. Under such a constraint on cost, an image formation apparatus has a memory configuration designed so that processing a job can be more prioritized.
For example, Japanese Laid-Open Patent Publication No. 2014-238665 discloses an image formation apparatus in which a first OS in which by using a hardware resource a processing involved in image formation is done by device control firmware and a second OS distinguished from and located on the first OS are each configured to be operable. When a predetermined specific state is sensed as the processing is done in the device control firmware, the device control firmware performs control to start the second OS and also performs control to perform a login process for the second OS. In this image formation apparatus, a first OS user name is used as a second OS user name to simplify a login procedure to allow a second OS login procedure to be performed fast.
In the image formation apparatus disclosed in Japanese Laid-Open Patent Publication No. 2014-238665, when a job such as image processing is generated, and a resource such as memory runs short, it is necessary to deliver over a resource to the first OS of body control, and accordingly, a logout process for the second OS's resource-releasing will be required. The period of time required for this logout process may delay starting execution of image processing.
In a conventional image formation apparatus, a form of using a memory to co-establish prioritizing job-processing and rapidly switching and thus running a plurality of OSs is not considered. Accordingly, for example, when a job which requires authentication is executed on an application on a guest OS, and a system memory runs out of resource, a period of time required for a processing to restore a content of the system memory arises, and a delay is caused when switching from a host OS to the guest OS and running the guest OS. As a result, an issue arises such as degradation of usability for processing the job, and reduction in productivity.
In an image formation apparatus, an operation utilizing a function of a guest OS which does not affect processing a job is permissible, however, when a guest OS function in liaison with processing the job is utilized, rapid switching to the guest OS from the host OS is required.
The present inventors have found a new issue, i.e., rapidly switching and thus running a plurality of OSs while prioritizing processing a job. However, such a new issue cannot be solved by simply applying a conventional hypervisor etc. to an image formation apparatus.
Accordingly, there is a demand for a novel configuration in an image formation apparatus for running a plurality of OSs simultaneously while prioritizing processing a job.